Switch mounting structure



Sept. 13, 1966 R. E. LARKIN SWITCH MOUNTING STRUCTURE Ci Sheets-Sheet 1 Filed March 9, 1965 Sept. 13, 1966 R. E. LARKIN SWITCH MOUNTING STRUCTURE 5 Sheets'Sheet 3 Filed March 9, 1965 Sept. 13, 1966 R. E. LARKIN SWITCH MOUNTING STRUCTURE 5 Sheets-Sheet 5 Filed March 9, 1965 3,272,461 SWITCH MOUNTING STRUCTURE Robert E. Larkin, Waukesha, Wis, assignor to Cutler- Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Filed Mar. 9, 1965, Ser. No. 438,345 5 Claims. (Cl. 248-27) This invention relates to an improved mounting means for switches.

More particularly the invention relates to an improved means for mounting float responsive switches to a sump pump motor.

Heretofore sump pump switches have commonly been mounted to the motor by a threaded bushing which extends from the switch frame through an aperture in the motor housing and have been held in place by a nut threaded onto the exposed end of the bushing. In many instances the bushing length has been limited and the thread engagement small, thus hindering a tight and long lasting connection. A loose connection would allow the switch to rotate about the bushing, thus disturbing the preset tripping points of the switch to cause faulty pumping action.

It is therefore an object of this invention to provide an improved switch mounting means which is inexpensive to manufacture.

It is a further object of this invention to provide a rigid mounting means for a switch which utilizes portions of the switch housing and the member to which it is to be mounted to achieve its rigidity.

These and other objects will become apparent in the following specification and claims when taken in conjunction with the drawings, wherein:

FIGURE 1 is a top plan view of a switch mounted to a device;

FIG. 2 is a front elevational view of the switch and device of FIG. 1 with a portion of the switch housing broken away;

FIG. 3 is a sectional view taken along line 33 of FIG. 1;

FIG. 4 is an enlarged view of a portion of FIG. 3;

FIG. 5 is a view like FIG. 2 with the switch cover removed and showing a feature of the invention;

FIGS. 6 and 7 are plan and side elevational views, respectively, of a mounting member incorporated in the invention;

FIG. 8 is a top plan view of a modified version of the invention; and

FIG. 9 is a front elevational view of the device of FIG. 8.

In the drawings there is shown in FIGS. 1-5, portions of a motor 2 having a cover 4 and a casing 6. The cover 4 has a terminal housing 8 open to the top to provide for electrical connection to the motor. Housing 8 is normally provided with holes for receiving screws 10 which fasten a cover member to the housing. A hole 12 is also provided in the cover 4.

A switch 14, which has an operator 16, is secured to a mounting plate 18 by a pair of rivets 20 (FIG. 3). The mounting plate 18 has a leg 18a at its upper end and a pair of tabs 18b near its lower end, all of which extend at approximately right angles to the mounting plate and in the same direction.

Mounting plate 18, with the switch 14 attached, is mounted to one leg of a U-shaped frame member 22 by sliding the leg 18a downward in a slot open to the top of that leg of the frame 22. The portion of the leg 18a which lies beyond the frame is wider than the slot and traps the upper end of mounting plate 18 to the frame against horizontal movement. The tabs 18b extend through corresponding slots in the frame and are sub- United States Patent sequently clinched over to hold the lower end of mounting plate 18 against the frame. An opening is also provided in that leg to allow the switch operator 16 to extend therethrough. The bight portion of U-shaped frame 22 is also provided with an offset portion 26 which has an opening 28 therein.

A commercially available molded snap grommet 30 (shown specifically in FIGS. 4, 6 and 7) of nylon or the like has a flanged end, or collar 32 and a barrel portion 34 extending outwardly therefrom. The barrel portion 34 is provided with a pair of diametrically opposed openings in its surface and each opening contains a pair of spring fingers 36 and 38 formed integral to the grommet at the outer end of the opening. Each finger has an inclined surface extending from its connected end toward the flanged end of the grommet and projects beyond the surface of the barrel. Each finger has at its free end a plurality of equally spaced steps which project upwardly to meet the top of its inclined surface. The steps of fingers 36 are closer to the flanged end 32 of grommet 30 than are those of fingers 38 and the distance between the last step of fingers 36 and the first step of fingers 38 is equal to the length of each step.

The design of grommet 30 is such that the barrel of the grommet may be pushed into a hole of slightly larger diameter than the barrel itself, such as opening 28 of frame 22 and hole 12 of motor 2. Upon pushing the grommet 30 through opening 28 and into hole 12 the forward edge of the wall of hole 12 cams the fingers 36 and 38 inwardly of the barrel due to the inclined surfaces. The fingers spring outwardly once the stepped portion of the fingers clear the rear edge of the hole 12 and the grommet is seated. The plurality of steps are provided on the fingers to facilitate various thicknesses of material in which the opening may be formed, or in this instance, a plurality of thicknesses of material. Once the fingers 36 and 38 have sprung outwardly behind the rear edge of the hole 12 the grommet 30, and therefore frame 22, is locked against linear movement relative to the motor 2, as shown in FIG. 5. While the grommet 30 has been hereindescribed as being inserted from the frame side, it is also contemplated in this invention that where clearance and other reasons dictate, the grommet may be inserted from the device side.

Rotation of the frame 22 about the grommet 30 when mounted upon the motor greatly facilitates the wiring of the switch 14. Lead Wires from the motor extend to a terminal block mounted in the terminal housing 8. The wires which connect the switch 14 to the terminals of the motor are passed through the grommet 30 and up into the terminal housing 8 as shown in FIG. 3. The switch 14 may be either a single or a double pole switch and each pole has a terminal at each end of the switch. In the particular application shown in the drawings only one pole of a double pole switch is used and therefore only two connecting wires are shown, a wire being connected at each end of switch 14. While the sequence of wiring the switch is immaterial, FIG. 5 shows the frame 22 rotated after the top terminal has been wired so that the terminal that was on the bottom is now at the top and may be easily wired. Upon wiring this terminal the frame is rotated back to its desired position and a cover member 40 is snapped in place over the frame 22.

Cover member 48 is a U-shaped member molded of a resilient material such as nylon or the like having a peripheral flange along each side. The bight of the cover forms the front wall of the switch enclosure and the legs of the cover form the top and bottom walls of the enclosure. The cover is slid onto the frame 22 from the front so that the flanges overlie the outer edges of the legs of the frame to position the cover. A pair of cam lugs 42 are formed on the inside outer ends of each of the legs of the cover 40 and snap over the top and bottom edges of the bight portion of the frame to hold the cover to the frame.

Cover member 40 is also provided with a cover plate 44 which is riveted to one leg of the cover, the leg being the top of the cover in this instance. Cover plate 44 extends rearwardly of the switch enclosure and is formed to comply with the top plan of the terminal housing 8. Clerance apertures are provided in the cover plate for screws which secure the cover plate 44 over the terminal housing. With the cover 40 and its cover plate 44 in place, the frame 22 and switch 14 are held to the motor against rotation.

FIGS. 8 and 9 show a modified version of the invention wherein the motor 2 and switch frame 22 are provided with a second hole to receive a second grommet 30. In this version the motor may or may not have a terminal housing, but in either instance, the cover plate 44 is not utilized. If the motor has a terminal housing, the terminal housing cover 48 provided with the motor is used to cover the housing. The frame 22 and switch 14 are assembled to the motor 2 as described before and the switch is wired in the same manner. However, to prevent the switch from rotating after it has been wired, a second grommet 30 is then pushed into the second hole. The cover 40 without the cover plate 44 is then snapped over the switch frame 22 and is held in place by the lugs 42.

While the invention has been described in connection with a switch mounted to a sump pump motor in the foregoing, it is apparent that the invention is susceptible of various modifications to be utilized in other situations without departing from the scope of the appended claims.

I' claim:

1. For mounting an enclosed electric switch unit on a device having an aperture extending through a wall thereof, the combination with a switchenclosure having a frame and cover member, said frame having an aperture arranged to be in corresponding alinement to that in the device, of attaching and securing means comprising a grommet for penetrating and seating in the alined apertures of the frame and the device, said grommet having a collar seating against a wall adjacent the periphery of one of said apertures and having resilient portions which overlie and grip a wall adjacent the periphery of the other of said apertures which is opposed to the wall first mentioned when said grommet is seated, and further comprising means in engagement with said enclosure and said device to prevent rotational movement of the switch unit about said grommet.

2. For mounting an enclosed electric switch unit on a device having an aperture extending through a wall thereof, the combination with a switch enclosure having a frame and cover member, said frame having an aperture arranged to be in corresponding alinement to that in the device, of attaching and securing means comprising a grommet for penetrating and seating in the alined apertures of the frame and the device, said grommet having a collar seating against a wall adjacent the periphery of one of said apertures and having resilient portions which overlie and grip a wall adjacent the periphery of the other of said apertures which is opposed to the wall first mentioned when said grommet is seated, and further comprising means extending from said cover and in engagement with said device to prevent rotational movement of the switch unit about said grommet.

3. The combination according to claim 2 wherein said cover is removable and the frame is free to rotate about said grommet seated in the alined apertures of the frame and the device when the cover is removed.

4. For mounting an electric swi-tch unit on a device having a first and second aperture extending through a wall thereof, the combination with a switch mounting frame having a first and second aperture arranged to be in corresponding alinement with those in the device, of attaching and securing means comprising a grommet for penetrating and seating in the alined apertures of the frame and the device, said grommet having a collar seat ing against a wall adjacent the periphery of one of said apertures and having resilient portions which overlie and grip a wall adjacent the periphery of the other of said apertures which is opposed to the wall first mentioned when said grommet is seated, and further comprising a second grommet like the first mentioned grommet seated in said second alined apertures of the frame and the device to prevent rotational movement of the switch unit about the first mentioned grommet.

5. For mounting an electric switch unit on a device having at least one aperture extending through a wall thereof, the combination with a switch mounting frame having at least one aperture arranged to be in corresponding alinement with that in the device, of attaching and securing means comprising a grommet for penetrating and seating in the alined apertures of the frame and the device, said grommet having a collar seating against a wall adjacent the periphery of one of said apertures and having resilient portions which overlie and grip a wall adjacent the periphery of the other of said apertures which is opposed to the wall first mentioned when said grommet is seated, said resilient portions being cammed inwardly when said grommet is pushed through the alined apertures and springing outwardly when said grommet is seated to allow the frame to be secured to the device by pressing said grommet through said apertures.

References Cited by the Examiner UNITED STATES PATENTS 2,424,757 7/1947 Klumpp 174153 2,673,300 3/1954 Furnas et a1 31071 3,082,470 3/1963 Fork 162 3,162,411 12/1964 Duggan 248--56 CLAUDE A. LE ROY, Primary Examiner.

I. F. FOSS, Assistant Examiner. 

1. FOR MOUNTING AN ENCLOSED ELECTRIC SWITCH UNIT ON A DEVICE HAVING AN APERTURE EXTENDING THROUGH A WALL THEREOF, THE COMBINATION WITH A SWITCH ENCLOSURE HAVING A FRAME AND COVER MEMBER, SAID FRAME HAVING AN APERTURE ARRANGED TO BE IN CORRESPONDING ALINEMENT TO THAT IN THE DEVICE, OF ATTACHING AND SECURING MEANS COMPRISING A GROMMET FOR PENETRATING AND SEATING IN THE ALINED APERTURES OF THE FRAME AND THE DEVICE, SAID GROMMET HAVING A COLLAR SEATING AGAINST A WALL ADJACENT THE PERIPHERY OF ONE OF SAID APERTURES AND HAVING RESILIENT PORTIONS WHICH OVERLIE AND GRIP A WALL ADJACENT THE PERIPHERY OF THE OTHER OF SAID APERTURES WHICH IS OPPOSED TO THE WALL FIRST MENTIONED WHEN SAID GROMMET IS SEATED, AND FURTHER COMPRISING MEANS IN ENGAGEMENT WITH SAID ENCLOSURE AND SAID DEVICE TO PREVENT ROTATIONAL MOVEMENT OF THE SWITCH UNIT ABOUT SAID GROMMET. 